Building a Chemistry Calculator for mixing fluids

[Keegan4123]

I am trying to build a calculator for a common task that calculates the required amount of fluid needed in a mixture to achieve the desired temperature.

Issue I have is the chemistry formula solves for 1 variable, but I need to solve for 2. There can only be 2 exact numbers given the variables, so not sure how to build the forumula.


Known Values
temp1 30.00
temp2 50.00
tempfinal 37.50
massttotal 36.00

Unknown Values
mass1 ??
mass2 ??
Total 36.00


Single Mass Formula m2 = m1 (T1 - Tf) / (Tf - T2)
or
m1 = m2 (T2 - Tf) / (Tf - T1)

Book1.xlsx
	A	B	C	D	E	F	G	H	I	J
1	Known Values
2	t1	30.00			Single Mass Formula		m2 = m1 (T1 - Tf) / (Tf - T2)
3	t2	50.00					or
4	tf	37.50					m1 = m2 (T2 - Tf) / (Tf - T1)
5	mt	36.00
6						Calculated using above formula			M1	13.5
7	Unknown Values								M2	22.5
8	m1	13.50
9	m2	22.50
10	Total	36.00
11
Sheet1

Cell Formulas
Range	Formula
J6	J6	=B9*(B2-B4)/(B4-B3)
J7	J7	=B8*(B3-B4)/(B4-B2)
B10	B10	=SUM(B8:B9)

 

[BSALV]

you can do it with goalseek

Map1
	A	B	C	D
1	Known Values
2	t1	30
3	t2	50
4	tf	37,5
5	mt	36
6
7	Unknown Values
8	m1	22,5
9	m2	13,5		0
10	Total	36
Blad1

Cell Formulas
Range	Formula
D9	D9	=SUMPRODUCT(B2:B3,B8:B9)/B5-B4
B9	B9	=+B5-B8
B10	B10	=SUM(B8:B9)

 

[Keegan4123]

@BSALV
That doesnt quite work. I should of posted this mini sheet instead.
I don't know m1 or m2. When I tried your formulas it comes up as incorrect numbers. (short by 1)

Book1.xlsx
	A	B	C	D	E	F	G	H	I	J
1	Known Values
2	temp1	30.00			Single Mass Formula		m2 = m1 (T1 - Tf) / (Tf - T2)
3	temp2	50.00					or
4	tempfinal	37.50					m1 = m2 (T2 - Tf) / (Tf - T1)
5	masst	36.00
6						Calculated using above formula (what b8 and b9 should be)			M1	13.5
7	Unknown Values								M2	22.5
8	mass1
9	mass2
10	Total	0.00
Sheet1

Cell Formulas
Range	Formula
B10	B10	=SUM(B8:B9)

 

[Marcelo Branco]

Try

31052022 Testes.xlsm
	A	B
1	Known Values
2	temp1	30
3	temp2	50
4	tempfinal	37,5
5	masst	36
6
7	Unknown Values
8	mass1	22,5
9	mass2	13,5
10	Total	36
Plan7

Cell Formulas
Range	Formula
B8	B8	=((B3-B4)/(B4-B2)*B5)/(1+(B3-B4)/(B4-B2))
B9	B9	=((B2-B4)/(B4-B3)*B5)/(1+(B2-B4)/(B4-B3))
B10	B10	=SUM(B8:B9)

M.

 

[Marcelo Branco]

It's a system with two unknowns (m1 and m2) and two equations

m1 = m2 (T2 - Tf) / (Tf - T1)
m1+m2=B5

Where
(T2-Tf)/(Tf-T1) = (50-37,5)/(37,5-30) = 1,666667
B5 = 36
m2=36-m1

So

m1= (36-m1)*1,666667

2,666667m1 = 36x1,666667

2,666667m1 = 60

m1 = 22,5

M.

 

[BSALV]

Map1
	A	B	C	D	E	F	G	H	I	J
1	Known Values
2	t1	30			Single Mass Formula		m2 = m1 (T1 - Tf) / (Tf - T2)
3	t2	50					or
4	tf	37,5					m1 = m2 (T2 - Tf) / (Tf - T1)
5	mt	36
6						Calculated using above formula			M1	22,5
7	Unknown Values								M2	13,5
8	m1	13.5							M	36
9	m2	22.5							T	37,5
10	Total	#NAAM?
11
Blad1

Cell Formulas
Range	Formula
J6	J6	=+B5*(B4-B3)/(B2-B3)
J7	J7	=+B5-J6
J8,B10	J8	=SUM(J6:J7)
J9	J9	=SUMPRODUCT(B2:B3,J6:J7)/SUM(J6:J7)